A current OLED backplane comprises a plurality of sub-pixels arranged in a matrix, as illustrated in FIG. 1, each sub-pixel including a pixel electrode region 1 and a passivation-layer via-hole region 2, a passivation-layer via hole being used for connecting a drain electrode of a thin film transistor (TFT) on a bottom layer and a pixel electrode on an upper layer. A fabrication process of the above-described OLED backplane comprises: as illustrated in FIG. 2, forming a passivation layer 3 on a substrate having a TFT pattern (not illustrated) formed thereon; forming a color filter 4 on the above-described substrate having the passivation layer 3 formed thereon, as illustrated in FIG. 3, depositing a resin on the substrate having the color filter 4 formed thereon, to form a flattening layer 5, the flattening layer 5 being used for flattening the color filter 4 to ensure continuity between the passivation-layer via hole and the pixel electrode, due to a relatively large thickness of the color filter 4. As illustrated in FIG. 4, Indium Tin Oxides (ITO) is deposited on the above-described substrate having the flattening layer 5 formed thereon, and a transparent electrode 6 is formed on the color filter by a patterning process. The transparent electrode 6 covers a region including the pixel electrode and the passivation-layer via hole, and is used as the pixel electrode and connected with the drain electrode of the TFT through the passivation-layer via hole. As illustrated in FIG. 5, a pixel defining layer 7 is formed on the above-described substrate including the transparent electrode 6, the pixel defining layer 7 is located around each sub-pixel, for separating adjacent sub-pixels, and cooperating with gate lines and data lines to ensure that light emitted by each sub-pixel will not affect other sub-pixels. On the above-described substrate including the pixel defining layer, an organic light-emitting layer and a metal electrode (not illustrated) are sequentially formed to complete the preparation of the backplane.
It can be seen that, the conventional fabrication process of the OLED backplane is relatively complicated.